Drills are used in all facets of manufacturing. All drills suffer from a basic problem that the base of the drill bit is retained in a chuck while the tip is free to cantilever. The tip of the drill bit not only "wobbles"on the drilling surface as the drill is initially advanced, reducing the accuracy of the position of the hole being drilled, but also "wobbles"as the drill bit is advanced forming an oversized hole.
Pilot holes may be punched or drilled with a short small diameter drill bit. The use of prior holes improves the accuracy of the drilled hole. However, this requires an additional manufacturing step, which adds manufacturing costs and production time.
Drill assemblies are currently commercially available from The Budd Company. These drill assemblies have a bushing, which guides the drill bit to minimize "wobbling". However, the bushing still allows for 8/1000 of an inch (0.008") variance on all sides resulting in oversized holes. Further, this bushing wears down quickly requiring frequent replacement. Still further, the prior art drill assemblies are relatively noisy dung operation, increasing concerns of health and safety of workers in close proximity of the drill.
An additional problem with the prior art drill assemblies is that the shavings or dust which is generated by the drill bit has a tendency to foul up the bushing, causing the assembly to seize up within a couple of hours. Vacuum hoses are commonly used to extract shavings and dust. Even with a vacuum system, these drill bit assemblies must still be replaced every 2,000-5,000 hours.